Electron gun mounting



ay 11, 1948. s V FQRGUE 2,441,315

ELECTRON GUN MOUNTING Filed Jan. 28-, 1946 2 Sheets-Sheet 1 TTORNEY y 11, 1943" s. v. FORGUE 2,441,315

A ELECTRON GUN MOUNTING Filed Jan. 28, 1946 2 Sheets-Sheet 2 INVENTOR ly STGHIe VFOT U TTORNEY Patented May 11, 1948 2,441,315 ELECTRON GUN MOUNTING Stanley V. Fcrgue, Cranbury, N. J., assignor to Radio Corporation of America, a corporation of Delaware i Application January 28, 1946, Serial No. 643,925

7 Claims.

This invention relates to mounts for the oathode, control electrode and first anode of a television cathode ray transmitting tube, such as disclosed, for example, in the application of Paul K. Weimer, filed September 16, 1944, Serial No. 554.494, now Patent #2433941, although it is not limited thereto.

An object of the invention is to mount the elements of the gun rigidly together so as to be essentially free from microphonics.

Another object of the invention is to construct the mounting of the gun elements so that they may be readily assembled in accurate spaced relation to each other.

Other objects of the invention will appear in the following specification, reference being had to the drawings, in which:

Fig. 1 is a longitudinal section through the gun and the mounts therefor.

Fig. 2 is an elevation of the anode cylinder of the gun.

Fig. 3 is an end view of the anode cylinder, as viewed from the right of Fig. 2.

Fig. 4 is an elevation of the dynode end of the anode before being inserted in the cylindero Fig. 2.

Fig. 5 is a view of the dynode end of the anode, as viewed from the right in Fig. 4.

Fig. 6 is an elevation of the grid cylinder before the end cap is inserted therein.

Fig. '7 is an end view of the grid cylinder of Fig. 6.

Fig. 8 is a sectional view of the cathode of the gun.

Fig. 9 is an end view of the cathode, as viewed from the right in Fig. 8.

Fig. 10 is a plan view of the gun mount,

Fig. 11 is a sectional elevation, taken on the line H-H of Fig. 10.

Fig. 12 is a view of the two clamps in sepa rated position which grip the heater element, shown in Fig. 1.

Fig. 13 is a plan view of the clamps of Fig. 12.

Fig. 14 is a modification.

Referring to Fig. 2, the anode has a cylindrical portion l with a flanged end 2. The cylindrical portion I has a plurality of openings 3, four in in position thereover, as appears in Fig. 1.

number, as indicated in this figure. These open- V 2 ing gas out of the gun and in reducing heat conduction towards the base of the gun.

The anode has end 4 to which is welded a cup 5 (see also Fig. 5) which in the final operation of the gun assembly is inserted inside of the cylinder l and the two parts are welded together, as appears in Fig. 1. The anode end 4 has a thin sheet 6 of silver-magnesium alloy clamped This thin sheet of alloy constitutes the first electrode or dynode of the multiplier unit, as particularly described in the application of said Paul K. Weimer. I

The grid or control electrode consists of a cylinder I, as shown in Fig. 6. This is somewhat smaller than the anode cylinder l of Fig. 2, so as to fit in spaced position therein. This cylinder also has a flanged end 8 and from the flanged end is stamped or punched a connector 9, to which may be soldered the grid conductor (not shown) entering the stem of the tube. When this grid connector is punched from the tube, it, of course, leaves a slot Ill therein (Fig, 7). The grid cylinder 1 also has a plurality of holes ll, say four, for increasing the resistance for high frequency heating in the degassing operation, for ease of pumping gas out of the gun and for reducing heat conduction. A cap 12, not shown in Fig. 6 but shown in Fig. 1, is inserted inside the grid cylinder 1 and is welded thereto. The grid cylinder and cap may both be made of non-mag netic stainless steel tubing. The grid cap 52 has an aperture I3 of the order of forty mils, although this may be varied considerably in either direction depending upon the operating characteristics desired of a given gun. There isan aperture M of about forty mils (not critical) in the dynode end parts 4 and 5 of the first anode, while the first dynode surface 6 of sliver-magnesium alloy has a small beam aperture of from a fraction of a mil to several mils again depending upon the operating characteristics desired.

The cathode in Figs. 8 and 9 consists of a main cylinder l5 having an integral flange IS. The cylinder l5 may have a plurality of openings IT, eight being indicated in the drawing, to increase the resistance and high frequency heating in the degassing operation for ease of pumping gas-out of the gun and for reducing heat conduction. The cathode end is of standard construction. consisting of a cylinder It in which the cathode cylinder l5 fits and to which it'is welded. Cylinder l8 has an inturned flange IS. A stub cylinder 20 is positioned in the cylindrical opening of the flange- I9 and has an outturned flange 2]..

A cap 22 has a flange 23 fitting against the flange 2i. Flanges l9, 2i and 23 are fastened together, preferably by Welding. The end 24 may have the usual thermoactive oxide coating and an insulated heater coil 25 (Fig. l) is mounted inside the cylinders I8, 20 and cap 22. This heater coil has the two resistance wires 25, 27 reversely wound, as is usual in such heaters.

The gun mount 28 consists of a double drum or cup having a disc or base 29 stamped to have a circular flange or rim 3!) with a flat disc 3|, from which depends the circular rim 32, as shown in Figs. 10 and 11. The disc 3i of this mount is punched at 33 and 34 so as to have depending lugs 35, 36 extending therefrom. Cups 31, 38 are positioned on opposite sides of the disc end 29 with their bases 39, 40 in contactwith the base 29. These three bases are then welded together. The three parts have openings Al, 42 merging together for passage of the cathode cylinder heater insulator, later referred to, and the grid wire 9, respectively.

The various elements of the gun may be assembled by several possible methods, one of which is as follows:

One or more mica washers, shown as a single insulator 43, are placed over the cathode cylinder l and against the flange IS. A flanged metal washer 44 is slipped over the cylinder l5 and the mica is pressed tightly against it. The washer then is welded to the cylinder [5 to hold the parts in place. A mica insulator washer 45 is then placed on top of mica insulator 43 and the cathode assembly is inserted in the gun mount 28 with the insulator 45 resting against the base 39 of cup 31. A metal washer 48 is placed against insulator 63 in cup 31 and, with a suitable assembly jig and press, the rim of cup 31 is turned over at 59. The cylinder l8 of the standard cathode assembly is next slipped over the end of cathode cylinder l5 and, after being positioned by a suitable jig to give correct cathode-grid spacing, it is welded into place on the cathode cylinder. Insulator 46 is next placed against the base 40 in cup 38 and the grid cylinder assembly is placed with the flange 8 against the insulator 46. The insulators have small holes through which the grid connector 9 may pass when this assembly is made. Another insulator 41 is placed in cup 38 against flange 8 of the grid cylinder. The anode cylinder is then placed in position with the flange 2 in cup 38 resting against insulator 41. The rim of cup 38 is then turned over at 49 by means of the assembly jig previously mentioned. The assembly jig incorporates suitable mandrels to produce the correct coaxial alignment of the several cylinders during the assembly operation,

The heater wires 26, ZIare welded to conductors 5!, 52 and ceramic insulator 53 is placed over the rods. Heater straps 54, 55 (Figs. 12 and 13) ar then welded in proper position around insulator 53. The heater assembly is then placed inside the cathode cylinder l 5 and the ends of the heater strap 55 are welded to lugs 35, 36 of the gun mount 28. The parts are now all firmly clamped in position in the gun mount and cannot move in relation to each other, no matter how roughly handled.

The cathode conductor 60 is welded. to the flange I 5 and the grid conductor to lug or connector 9. The anode conductor, not shown, may be connected to the rim 32 of the mount 28, as the flange 2 is clamped in direct contact with the mount at the, turned-over edge 49, The flanges 8 and -16 of the grid and cathode cylinders-have less diameter than the cups 3? and 38 and hence are spaced and insulated from the mount.

If it is desired to surround the gun with other elements, such as the multiplier units and associated parts, as disclosed in my application, filed February '7, 1946, Serial No. 6 3.8375, these are slipped over the gun in proper position and the cup 5 of the anode end assembly is slipped into the anode cylinder 5 welded thereto, thus completing the assembly oi the gun.

U-shaped straps either singly or in pairs. are welded to the outside surface of drum rim S2 and the ends are bent around hollow ceramic rods 51 and then welded together. There may-be as many of these rods as desired, but four spaced apart are sufiicient. Metal rods 58 extend through the ceramic insulators and are welded to supports which are sealed in the tube stem (not shown) when the complete unit is assembled in the glass envelope.

In the modification of Fig. i i the heater strap (5! is made somewhat longer than strap 55 of Fig. 13 and the ends are turned anguiarly to fit against the rim se of the mount, to which they are welded. The other parts would be similar to those shown in Fig. 1 and are not illustrated in Fig. l l.

The ceramic rods 51 may be used to support the-multiplier elements around the gun, but these units are not illustrated herein, as this is the subject of my said copending application.

I claim:

1. In cathode ray tubes, a metal cathode cylinder having a flange at one end, an insulation washer fitting around the cathode cylinder, 9. metal washer in contact with the outside of said cylinder clamping the insulation washer against said flange, a metal cup having a central opening in its base, an insulation washer engaging the inside of the base of said cup, said cathode cylinder extending through said central opening with the first-mentioned washer bearing against the second-mentioned washer, and a metal washer bearing against the first-mentioned washer, the outside wall of said cup being turned over to clamp all said washers in said cup.

2. In cathode ray tubes, a metal cathode cylinder having a flange at one end, an insulation washer fitting around the cathode cylinder, a metal washer having a, circular flange around its opening in contact with said cylinder, said circular flange being welded to the cylinder with the insulation washer clamped thereby against the cathode cylinder flange, a metal cup having a central opening in its base, an insulation washer engaging the inside of the base of said cup, said cathode cylinder extending through said central opening with the first-mentioned washer bearing against the second-mentioned washer, and a metal washer bearing against the first-mentioned washer, the outside wall of said cup being turned over to clamp all said washers in said cup.

3. In cathode ray tubes, 2. metal cup having a central opening, a cathode cylinder extending through said opening and having a flange, means for clamping the flange against the base of said cup, a heater element inside said cathode and means for supporting said heater element on the inside wall of said cup.

4. In cathode ray tubes, a metal cup having a central opening in its base, an insulation washer on the base of said cup, a metal grid cylinder having an end flange onsaid insulation washer,

an insulation washer on the flange of said grid.

cylinder, and an anode cylinder having an end flange on the last-mentioned insulation washer,

the wall of said cup being turned over at the top to clamp said flanges and washers against the base thereof.

5. In cathode ray tubes, a main cup, a pair of smaller cups, said cups having central openings, the bases of the auxiliary cups being secured to the opposite sides of the base of the main cup with the said openings in alignment, a cathode cylinder having a flange at one end, a larger grid cylinder having a flange at one end, said flanges being of lesser diameter than the inside diameter of said auxiliary cups, a still larger anode cylinder having a flange at one end, said cathode cylinder extending through said central openings with its flange in the inner auxiliary cup, said grid cylinder being mounted around said cathode cylinder with its flange in the outer auxiliary cup, said anode cylinder being mounted around said grid cylinder with its flange inside said outer cup, insulation discs in said cups with central openings fitting around said cylinders and resting against sides of the cathode and grid flanges and against the inner side of the anode flange, the walls of said auxiliary cups being turned over and compressing the flanges and insulation Washers in said cups.

6. In cathode ray tubes, a main cup, a pair of cups, said cups having central openings, the bases of the auxiliary cups being secured to the opposite sides of the base of the main cup with the said openings in alignment, a, cathode cylinder extending through said central openings,

grid and anode cylinders extending through one of said openings, all said cylinders having flanges clamped in said auxiliary cups, a plurality of supporting rods extending axially of said cups and spaced apart around the perimeter of the main cup, and means for securing the main cup to said rods.

'7. In cathode ray tubes, a main cup, a pair of smaller cups, said cups having central openings, the bases of the auxiliary cups being secured to the opposite sides of the base of the main cup with said openings in alignment, a cathode cylinder extending through said central openings, grid and anode cylinders extending through one of said openings, all said cylinders havin flanges clamped in said auxiliary cups, a plurality of supporting rods extending axially of said cups and spaced apart around the perimeter of the main cup, means for securing the main cup to said rods, a heater element inside said cathode cylinder and means for securing said heater element to the inside wall of the main cup.

STANLEY V. FORGUE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,125,279 Bieling Aug. 2, 1938 2,184,821 Uhlmann Dec. 26, 1939 2,244,358 Ewald June 3, 1941 

